Question

An empty pool being filled with water at a constant rate takes 8 hours to fill to $\frac{3}{5}$ of its capacity. How much more time will it take to finish filling the pool?

• A. 5 hr 30 min
• B. 5 hr 20 min
• C. 4 hr 48 min
• D. 3 hr 12 min
• E. 2 hr 40 min

Answer 1

The correct option is B 5 hr 20 min

Volume of pool that is empty is 1-$\frac{3}{5}$=$\frac{2}{5}$

Let it takes $x$ hr to fill $\frac{1}{5}$ part of pool

then $x\frac{3}{5}$=8

$x=\frac{40}{3}$

Time required to fill $\frac{2}{5}$ will be $\frac{40}{3}$x$\frac{2}{5}$=$\frac{16}{3}$=5+$\frac{1}{3}$ hr

Which is equal to 5 hr 60x$\frac{1}{3}$ minutes = 5 hr 20 min

So correct answer will be option B